1. Field
Example embodiments relate to non-volatile memory devices and methods of programming the same. Other example embodiments relate to non-volatile memory devices that move electrons between charge trap layers and through pad oxide layers. Example embodiments also relate to methods of programming a non-volatile memory device including moving electrons through pad oxide layers between charge trap layers of the same.
2. Description of the Related Art
Non-volatile memory devices, in which data may be electrically erased and programmed, preserve stored data even without a power supply. Such non-volatile memory devices include, for example, a flash memory.
A flash memory stores data by storing electric charges. Memory cells constituting a flash memory may be composed of cell transistors each including a control gate, a charge storage layer, a source and a drain. The flash memory changes a data value written in the memory cells by regulating electrical charge of the charge storage layer.
A mode in which a threshold voltage of a cell transistor is negative (−) due to negative charges in the charge storage layer is referred to as an erasing mode. A mode in which electrons are injected to the charge storage layer and a threshold voltage of a cell transistor is positive (+) is referred to as a programming mode.
The threshold voltage of the cell transistor may be changed by regulating the electrical charge of the charge storage layer. To regulate the electrical charge of the charge storage layer, hot electrons may be injected to the charge storage layer or may be ejected from the charge storage layer. If the hot electrons are injected or ejected, oxide in the charge storage layer may deteriorate.